Molten sodium chloride conducts electricity due to presence of:

A. Free electrons

B. Free molecules

C. Atoms

D. Free ions

The ability of molten sodium chloride (NaCl) to conduct electricity is primarily due to the presence of free ions. Therefore, the correct answer to your question is D. Free ions. Let’s delve deeper into why this is the case.

Understanding Ionic Compounds

Sodium chloride is an ionic compound made up of sodium ions (Na⁺) and chloride ions (Cl^-). In its solid state, these ions are held together in a rigid lattice structure, which prevents them from moving freely. This immobility is why solid sodium chloride does not conduct electricity.

The Role of Melting

When sodium chloride is heated to its melting point, it transitions from a solid to a liquid state. This process breaks the ionic bonds that hold the lattice together, allowing the ions to move freely. In this molten state, the sodium and chloride ions can move independently, which is crucial for electrical conductivity.

Conductivity Explained

Electricity is the flow of electric charge, and in the case of molten sodium chloride, that charge is carried by the free-moving ions. Here’s how it works:

• Ion Movement: When an electric field is applied, the positively charged sodium ions move towards the negative electrode, while the negatively charged chloride ions move towards the positive electrode.
• Charge Transfer: This movement of ions allows for the transfer of electric charge, which is what we measure as electrical conductivity.

Comparison with Other States

To further illustrate this point, let’s compare molten sodium chloride with its solid state and with a solution of sodium chloride in water:

• Solid State: In solid NaCl, the ions are locked in place and cannot move, so it does not conduct electricity.
• Aqueous Solution: When NaCl is dissolved in water, it dissociates into free ions, similar to the molten state. This solution can also conduct electricity due to the presence of free ions.

Conclusion

In summary, the electrical conductivity of molten sodium chloride is due to the presence of free ions that can move and carry charge. This principle is fundamental in understanding how ionic compounds behave in different states and environments. So, when you think about the conductivity of sodium chloride, remember that it’s all about those mobile ions!